From: Andreas Schwab <schwab@linux-m68k.org>
To: Jari Aalto <jari.aalto@cante.net>
Cc: 7227@debbugs.gnu.org
Subject: bug#7227: re-search-forward goes infinite loop with dash inside []
Date: Sat, 16 Oct 2010 15:54:17 +0200 [thread overview]
Message-ID: <m21v7qp7jq.fsf@igel.home> (raw)
In-Reply-To: <87eibqp847.fsf_-_@picasso.cante.net> (Jari Aalto's message of "Sat, 16 Oct 2010 16:42:00 +0300")
Jari Aalto <jari.aalto@cante.net> writes:
> Hm. The test case needs adjustment:
>
> ;; (1) Run C-x C-e, works:
>
> (re-search-forward "^\\([a-z0-9.-]+\\)+[ \t]+\\([0-9]+\\) +\\([a-z].*\\)")
> row2 1234 rest of line
>
> ;; (2) but C-x C-e below causes a loop
>
> (re-search-forward "^\\([a-z0-9.-]+\\)+[ \t]+\\([0-9]+\\) +\\([a-z].*\\)")
> ------------------------------------------------------------------------
> row2 1234 rest of line
>
>> Note that nested repetitions like \([...]+\)+ are bad in any case.
>
> This was only a test. The anchor "^" should help, and I assume the first
> '[a-z0-9.-]+' should be greedy, so it shouldn't take that long to
> resolve.
Not in the non-matching case. When the match against the dash line is
tried you get quadratic behaviour due to explosion of the search tree.
Andreas.
--
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5
"And now for something completely different."
next prev parent reply other threads:[~2010-10-16 13:54 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <r6eo4w45.fsf@blue.sea.net>
[not found] ` <1213200935.4147.62.camel@cyberelk.elk>
2010-10-16 13:42 ` bug#7227: re-search-forward goes infinite loop with dash inside [] Jari Aalto
2010-10-16 13:54 ` Andreas Schwab [this message]
2010-11-16 21:25 ` bug#7408: Linux patchutils: Development of the project? Jari Aalto
2010-11-16 21:59 ` Lennart Borgman
2010-11-16 22:21 ` Stefan Monnier
2010-11-17 4:47 ` jari
2010-11-17 8:25 ` Glenn Morris
2010-11-17 13:39 ` Stefan Monnier
2010-11-17 12:47 ` Štěpán Němec
2010-11-17 13:39 ` Stefan Monnier
2010-11-18 22:02 ` bug#7408: 23.2.1 dolist -- subr.el and cl-macs differ with nil-block return Jari Aalto
2010-11-21 5:45 ` Stefan Monnier
2010-11-21 9:08 ` jari
2010-11-21 17:49 ` Eli Zaretskii
2010-11-21 18:51 ` Stefan Monnier
2010-11-17 14:18 ` bug#7408: Linux patchutils: Development of the project? martin rudalics
2010-10-16 9:16 bug#7227: re-search-forward goes infinite loop with dash inside [] Jari Aalto
2010-10-16 11:27 ` Andreas Schwab
2010-10-16 11:39 ` Andreas Röhler
2010-10-22 7:55 ` bug#7227: Close bts:gnu Jari Aalto
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